I think I like the visual approach of the second site better — I mean, who doesn’t love repurposed periodic tables? (1, 2, 3, 4, 5) But the sheer variety, eclecticism, and particularity of visualization methods on display at the Milestones site is hard to beat, including EEGs, the invention of the Cartesian coordinate plane, the USA Today weather map, and other things you might not immediately think of when you think of data visualization.